Abstract
Beekeeping with honey bees (Apis mellifera) is important in tropical regions but only scant information is available on the possible consequences of global warming for tropical beekeeping. We evaluated the effect of heat stress on developmental stability, the age at the onset of foraging (AOF) and longevity in Africanized honey bees (AHBs) in the Yucatan Peninsula of Mexico, one of the main honey producing areas in the Neotropics where high temperatures occur in the spring and summer. We assessed the outcome of high stress temperatures on worker pupae of AHBs reared under a fluctuating temperature regime, emulating current tropical heat waves. This treatment involved a maximum fluctuating regime with the highest temperature peak of 40°C for 1 hour daily during six days. We compared treated pupae with control pupae reared at stable temperatures of 34-35.5°C. We estimated the influence of heat stress on development by analyzing fluctuating asymmetry (FA) in the size (n = 77) and shape of individuals (n = 118) and also the age at onset of foraging (AOF; n = 840) and total lifespan (n = 2443), traits that may affect the fitness of the colony. Our results showed that temperature regimes similar to those currently experienced by AHBs under field conditions did not affect overall body size except forewing length. However, bees that were reared under heat stress showed significant levels of FA in the shape of the forewing. High stress temperatures also decreased AOF and total lifespan. Our results show that changes occur in the phenotype and behavior of honey bees under heat stress. We discuss the effects and potential tolerance of AHBs to stressful temperatures.
Keywords
Heat waves, developmental stability, Apis mellifera, global warming, longevity, precocious foraging